Nice try by Trump's defence team. But it's the opposite. It's unusual to invoke the crime-fraud exception to attorney-client privilege, but the prosecutors are doing so because they think there's strong evidence of a crime having been committed in the conversation between him and his attorney, Corcoran. And that evidence is disastrous for Trump.
What appears to be the case is that Corcoran recorded and documented his conversations with Trump - like Cohen did. He was aware that Trump deliberately leaves no evidentiary trail of his own (nothing in writing*) and then blames everyone else for the bad things he does (as with Cohen and the payment to Stormy Daniels). So Corcoran made sure he had a complete record of what Trump said to him. And that conversation is probably going to confirm that Trump knowingly concealed the secret government documents.
Once those recordings are revealed, Trump is toast. Because in them, he's either going to tell Corcoran a lie that he didn't have the secret documents and he is trying to trick him into asserting to the government that this is so: "There are no secret documents at Mar-a-lago." Or he will admit he did have them and will ask Corcoran how to hide that fact. And in either case, it's going to be obstruction.
Corcoran then certainly tried to have a second attorney make the assertion that there were no classified government records at MAL and she refused unless words similar to "as represented to me by others" were added to her assertion. So basically, both attorneys were well aware that they needed to cover their butts because they both knew all about Trump's methods and the risks he was passing to them.
The judges plainly know Corcoran's recordings and contemporaneous documents exist and Corcoran must have told them it's so. They are pinning the tail on the donkey. And they are doing so at lightning speed for a court. Corcoran isn't the villain. Trump is. Corcoran is a witness for the prosecution. He's simply going through the motions of revealing the proof that Trump is the serpent in the MAL garden, not him.
Ouch.
I wonder how many of the classified documents Trump has already sold to the highest bidder (Russia, China, Saudi Arabia, Iran, North Korea). And whether the government will eventually be able to track this also, by following the money.
*Heck, he even ate and flushed his notes while in the White House!